Bacteriuria and pyuria are uniformly present in patients who have indwelling urinary catheters. Antimicrobial therapy may transiently eradicate the bacteria, but bacteriuria promptly recurs, and the infecting bacteria become progressively resistant to antibiotics. Antimicrobial (e.g., antibiotic and/or antiseptic) treatment of asymptomatic urinary tract infections (UTI) in catheterized patients has not been shown to be of benefit, as treated and untreated catheterized patients have a similar prevalence of infection a few weeks after the end of treatment, and an equal likelihood of developing symptomatic episodes of UTI (Nicolle, L. E., Drugs Aging 22(8): 627-39 (2005). Additionally, antimicrobial treatment of asymptomatic catheter-associated UTIs (CAUTIs) has been associated with the emergence of drug-resistant organisms, complicating management when symptomatic infections occur.
Studies have indicated that pre-colonization of the bladder with certain non-pathogenic strains of E. coli is a safe and effective way of preventing or reducing the in vivo incidence of urinary catheter colonization by a wide variety of uropathogens.